Help! Just when I think I have resolved the problem, it happens again - 5 batches tossed since the end of July! Goes into the mold fine, the next morning - spongy rising cheese (blue stilton, cheddar, bel paese, variety of DVI cultures)

Here's the rundown:1. I use vat pasteurized milk from an organic grassfed dairy. I purchase in one gallon plastic jugs. I am making cheese at home.2. Recently purchased a commercial refrigerator as my milk storage refrigerator seemed to have temp issues and I thought this might be creating a problem, this didn't solve the inflation problem.3. Moved all wine fermentation from basement to garage despite the fact the wine storage had no return air cross with the rest of the house, didn't solve the inflation problem. There is no air crossover between the garage and the house.4. After each failure - sanitized all counter spaces with clorox cleanup, mopped the floors with same.5.I always sanitize all of my equipment with star-san or sterilite tabs before making (obsessive personality is a wonderful thing in a cheesemaker).6. I have not made bread since Christmas.

I suspect it is a yeast problem but I can't seem to get rid of it. Our temperatures here have been high 95 to 105 but I live in a very low humidity area. Lots of wind this year but I haven't had windows open due to central air with temp at 72. Doors open and close on occasion for the dogs.

I have some fruit/veggies stored with the milk jugs in the commercial fridge. The cheese starts out looking great but by morning could be used to wash dishes!

What have I missed? I am tearing my hair out (but not around the cheese ) Thanks for any help!

Quick ideas:- Dog dandruff in the vicinity- Coliform contamination- Traces of Star-San in your own equipment- Cross contamination comes from the central AC

Have you tries switching milk or cultures? If not:- The issue could be from the farmer: Traces of udder-sanitizing substance. Antibiotics in the cow's diet. Traces of sanitizer in the bottling equipment- If this happens with the same culture sachet, the sachet itself may be contaminated- Are you sure the cows were fed only grass?

Are you using proper food-grade equipment? (No construction grade home-made PVC moulds or other hacks. You stir and cut curd with stainless steel utensils, etc.)

Well, I have attached photos - I can't seem to find directions on how to insert a photo into my reply..........

Milk - I have been cheesemaking with this milk since January. End of July is the first time I have had issues with this swelling.Cultures - it has occurred with a variety of different cultures, even with same cultures that come from different packaging.Certified Organic- No antibiotics, yes grassfed and they do not bring in hay, they raise their own. Vat pasteurized with no reports of any milk issues.All of my equipment is proper food grade.

I don't have enough understanding of coliform contamination to know what that really looks like but this spongy cheese does not have a "horrendous" odor.

Cross contamination from AC? Were you thinking of the wine or just moving air about in general?Dog Dandruff in the vicinity - well, dogs are in the house so may a good sterilization is in order for them

It does resemble coliform bacteria infection. This stuff can be in the environment though. The cheese wouldn't smell horrendous, but definitely an off odor. I have a hard time putting words on it. What type of environment do you live in? Country? I understand that if an animal eats the bacteria, spores can end up in the milk. Remember, pasteurizing doesn't kill all the stuff in it, though it does do a damn fine job. There might be enough remaining in it to allow for regeneration/infection.

The area I live in would be categorized as "small city" residential. Though I am an "edible landscape" person so on my large lot I have gardens, compost and perennial fruit (apricots, plums, grapes, apples,pears, raspberries, hops). The only thing different outdoors is some "logging" we did in July, cutting out some cedar trees and a diseased pie cherry tree (I am in eastern Washington btw).

Is it possible to easily test for coliform to figure out the potential contamination timeframe i.e. after pasteurization, during make?

I have some fruit/veggies stored with the milk jugs in the commercial fridge.

I'm not sure when this was, sometime in the past few months, but I remember LB posting something about there being more yeasts floating around in the air since fruit was ripening and so the yeasts had more sugars to eat - or something to that effect. The big part being more yeasts in summer-ish time. Since you have all those fruit trees and fruit co-habitating with the milk and cheese, maybe that's where it's coming from? (Assuming it really is yeast.) Try separating them and sanitizing the fridge again?

To me this looks like a coliform infection. Yeast smell yeasty like bread. Coliforms smell horrendous (fecal) as you have described.

IMHO this does not happen from a casual airborne contamination. The results are obviously dramatic and will not happen from just a few bacteria or yeast getting into the milk. Airborne contamination in your kitchen is what I call "sub-clinical" because there just aren't enough bad organisms to become dominant that quickly. Bacteria and yeast are everywhere, and you will almost always have tiny levels of contamination. One of the goals in cheesemaking is for the starter bacteria to dominate and overwhelm the contaminants.

So that being said, you obviously need to isolate the problem. Without being there and watching your make it's impossible to say with any degree of certainty, but here are some things to consider.

1- "Certified Organic" has nothing to do with sanitary practices. If there are coliforms in the milk, it's because of poor (unsanitary) procedures by the dairy farmer. Discuss this with your farmer. FYI - this is why raw milk gets such a bad rap. It's NOT the milk, it's the collection and handling.

2- The vat pasteurization may be inadequate. Ironically, this may never show up with liquid milk consumption, because the milk is at refrigeration temperatures. But inadequate pasteurization can become a real problem in a warm cheesemaking environment. Talk to them about the time and temperature, and how quickly they cool the milk afterwards.

3- Milk should never go above around 40-41F including when you are transporting it. Don't allow it to warm up before you start a make. Warm milk will allow bacteria to grow. Bacteria double their population every 20 minutes under proper conditions, so it doesn't take long for bad stuff to get a foothold.

Sailor,Thanks for the info-just to clarify, my comment was that it did NOT have a horrendous odor. The odor is kind of undefinable. You have raised several good points, especially with the heating. I will speed up the to culture temp-i make in four gallon batches in a bain Marie and I had set to warm slowly. I will also backtracked on these other solutions.

I agree with Karen's idea too. re-pasteurize to see if this problem occurs before or after you open your milk.Alternatively, you can also just get milk from another source and see what happens.

This looks like coliform to me and yes, you mentioned central AC so it is definitely possible that id brings this contamination into your sanitized area. The dogs may have something to do with it so again, you can eliminate the environmental aspect by trying to make this cheese with the same milk and cultures -at a friend's house. See what happens then. At the very least, it would tell you where to look.

as Sailor brought up some excellent points. Keeping the milk chilled during transportation is important. Do not keep it on the counter for too long either. You need to heat it up for cheesemaking gently, however if you take too much time, the milk will spend too much time in the median temperature where coliform grow. Same goes for improper pasteurization (either not bringing milk to proper heat or not chilling it fast enough). Organic has nothing to do with sanitation standards and it's not just being unsanitary, it's also using harsh udder and equipment detergents/cleaners/disinfectants and not assure that they don't taint your milk. These can seriously disturb the bacterial protection balance in your milk as well as the inoculation success during cheesemaking.

I have experienced coliform inoculation in the past. It doesn't have to have bad odor. It can smell yeasty and sweet.

I had this problem a few times, and I think it was from being too close to the fruit. See all the white powdery stuff on the grapes? That's yeast! And there is yeast on other fruits as well, just not as visible.

After that, I kept the fruit very separated from the milk, and have only had problems once or twice since then, and once was when my cow was getting mastitis, so the milk was off.

We just keep the fruit covered with napkins and kitchen towels on a table in the kitchen which I keep the milk several feet away from. If I run out of counter space, I put the milk in the dining room rather than on the table with the fruit on it.

I don't think it's fruit yeast (Oidium). Fruit yeasts are more a contamination and annoyance with destroying cheese rind flora. They seldom can grow crazy on acidic fresh cheese and take over in a few hours.